This application relates generally to the cooling of motors for vapor compression systems incorporated in air conditioning and refrigeration applications.
Vapor compression systems can use more compact motors operating at higher rotational speeds to provide power to components. By using more compact motors, a reduction in the size of the systems can be obtained. In addition, gains in motor efficiency may also be realized at high rotational speeds. However, some challenges associated with operating motors at higher rotational speeds include the generation of friction between the motor shaft and bearings and windage losses. Windage is a frictional force created between the rotating rotor of the motor and the environment surrounding the rotor, typically air or a working media, such as refrigerant vapor in the case of a hermetic driveline. Windage can create heat and reduce the operational efficiency of the motor.